The present invention relates to arc-welding guns and, in particular, to guns of the type having a flexible nozzle adapted to be bent into any desired configuration.
There have been a number of attempts to provide gas metal arc-welding guns with a flexibility that permits the nozzle to be bent into any desired curvature needed for reaching otherwise inaccessible portions of the work to be accomplished. Apparently, however, these attempts have not met with success. One such attempt, for example, employs a flexible electrode, but the electrode is provided as a separate piece coupled externally of a flexible gun barrel which carries the inert gas and welding wire to the point of application. One difficulty with such an arrangement is that the external flexible electrode, even though insulated, may produce damaging and unsafe sparking conditions particularly at the points where the electrode is coupled to the rest of the gun. Also, arrangements of this type have a limited rather than universal flexibility. Another arrangement incorporates the current-carrying electrode within a flexible tube disposed between the body of the gun and its nozzle, but these arrangements appear to be unnecessarily complex due in part to the manners in which they provide for a continuous feed of the welding wire as well as the continuous supply of the inert gas. Of perhaps greater significance, this arrangement uses a sleeve-like, braided electrode which is longitudinally flexible but which, at least, has a limited current-carrying capacity.
It is therefore an object of the present invention to provide a relatively inexpensive, simple, reliable metal arc-welding gun having a flexibility which permits the gun nozzle to be disposed in and to retain any desired bending configuration.
Another object is to provide an attachment for standard welding guns of the type under consideration, the attachment providing the guns with the desired nozzle flexibility.
A further object is to provide a flexible gas metal are welding gun which has a reverse bend capability if so desired and which, nevertheless, maintains its gas and welding wire passage in an open condition when so bent.
Another object is to provide a gun having the foregoing capabilities, the gun flexibility being provided in such a manner that its nozzle can be bent repeatedly over a long period of time without undue weakening.
A still further object is to provide a gun of this type which has a practically unlimited current-carrying capacity, the gun being capable of operating in a relatively cool and entirely safe manner regardless of the amperage.
Other objects and their attendant advantages will become apparent in the ensuing description.
The objects generally are achieved by employing a flexible, elongate, tubular electrode to provide the flexibility for the nozzle, the electrode being formed of electrically-conductive wire spirally wound to provide a tube-like structure capable of being bent into any set disposition. The electrode, most suitably formed of a multi-strand spiral, is encased in a flexible sleeve which, when the electrode is bent, effectively maintains the convolutions of the spiral in their formed disposition so as to avoid excessive spreading of the convolutions as well as excessive crimping which accompanies the spreading. This sleeve may include or be formed as an insulator, although the preferred arrangement is to directly wrap the bare wire electrode with a glass tape or the like, and to apply an insulating sleeve in a spaced relationship over the tape. Welding current, of course, is supplied through the wire electrode while inert gas frequently used in these welding operations is supplied coaxially of the wire in a manner which will be described. Guide means are mounted in the electrode bore to assure a smooth feeding of the welding wire.